Life Beneath Antarctic Ice

The WISSARD team

 UC Santa Cruz researchers on a drilling team in Antarctica found a fantastical realm where ice meets the sea

 by Hannah Hagemann

As Slawek Tulaczyk trudges across the ice of Antarctica, the crunch of his crampons is the only thing that tells him he’s on solid ground. He walks into blinding whiteness with the confident stride of someone who’s been there many times. One of his assistant researchers, graduate student Grace Barcheck, grips a handheld GPS device with numb fingers. Without it, they’d just be specks in a vast desert of ice.

Tulaczyk’s meticulous methods are both calm and routine. It’s essential for the UC Santa Cruz glaciologist to get anything done in this environment, which he describes as “being suspended in a snowball. Below you is white, above you is white. . . it’s complete sensory deprivation.” He and his fellow researchers endure their senses being turned inside out because they know the reward will be great: to prove that even in this unforgiving fortress of ice, one of the world’s harshest environments, things want to live.

Tulaczyk’s pursuit led him far beneath the surface of the ice, thousands of feet down to the “grounding zone.” Here, at the bottom of the vast ice slab, ice sits on muddy sediment and comes into contact with the ocean. This interface, where the ice sheet begins to float, may shelter the most isolated creatures on earth. It also holds Antarctica’s deepest secrets—including the fate of much of its ice. In January 2015, Tulaczyk and his team became the first scientists to tap into this eerie realm.

The project, called WISSARD (Whillans Ice Stream Subglacial Access Research Drilling), drilled down to an ecosystem directly beneath the ice shelf for the first time. Like weeds taking hold in sidewalk cracks, the hardy microbes, fish, and invertebrates under Antarctica have made the ice their home. Some of these organisms are among the planet’s most primitive species. They don’t need sunlight; they harness their energy from raw building blocks of life, like carbon and silica, obtained from weathered rocks.

The dynamics within the grounding zone also are a key to understanding the continent’s second-biggest chunk of ice: the West Antarctic Ice Sheet (WAIS). Climate change might set loose parts of this remote reservoir of frozen water, triggering a huge rise in global sea level. Finally drilling into and sampling the grounding zone, says Tulaczyk, “will really change how we think of that interface, how the two systems [seawater and ice] interact.”

In Antarctica’s desolation, there is silent power. The WAIS spans a Texas-size area with a volume of more than 700,000 cubic miles of ice. But even this frigid zone is vulnerable to global warming. If it melts entirely, the ice sheet would raise sea level 15 to 20 feet—enough to take out San Francisco Airport in the next 50 years, says Tulaczyk.

More than 40 scientists on the WISSARD project have studied the complex dynamics within the ice sheet for the past four years. The project’s goals are interdisciplinary: to gather data on the stability of the ice, and to study the creatures living beneath it.

The 4,000-foot-thick WAIS is the planet’s last ice sheet that sits on land below sea level. The sheet contacts an active tectonic rift zone, complete with volcanoes. Earth's geothermal heat, which rises to the surface everywhere on the planet, touches the underside of the ice sheet with particular vigor. The unique features of the ice sheet also make it susceptible to warming seas. A network of interior lakes and streams, an active rift zone beneath, and interactions between ice and open ocean all make the sheet vulnerable to thawing out—jeopardizing residents of coastal cities and low-lying islands worldwide.

During the 2013 field season, WISSARD researchers drilled a borehole through Whillans Ice Stream, a glacier within the ice sheetthat moves and flows. This stream feeds into the Ross Ice Shelf, the part of the WAIS that floats on ocean water. The ice shelf can gain thousands of feet of ice or lose it quickly, making it especially sensitive to climate change. WISSARD researchers were the first to access a body of water under the ice sheet, Lake Whillans, and find groundwater within it. This proved the ice sheet isn’t a rigid monolith, but a dynamic system with moving internal waterways.

Tulaczyk already had predicted a system of subglacial lakes and streams. He knows the setting well; he has been to Antarctica 11 times. Indeed, Antarctica is his meditative sanctuary. Like an artist who retreats to his countryside home to create work, Tulaczyk isolates himself on the ice. Of working on the ice sheet, he says: “You build an island that supports the people and supports the work on a piece of frozen ocean."

Tulaczyk's office at UC Santa Cruz is cluttered—not with papers, but with obtusely shaped plastic cases that look important. The mishmash of cases contains 10,000 pounds of equipment from WISSARD expeditions, he says. The yellow cases are data logging setups; the bulky black cases protect ice-penetrating radar gear. “The biggest pieces [of sediment cores] would be the length of the wall,” he says, motioning to the longest side of his office. “We’ve had a problem finding places to put it. My office becomes a junk yard.”

Drilling through a half-mile of ice is expensive, dangerous, and takes an army of people and equipment. But the work pays off with new findings—such as the first look at the grounding zone under the ice sheet in January. The interaction between ocean water and the grounding zone is like a zipper, Tulaczyk says. Ocean water erodes into the bottom of the ice shelf, zipping back the boundary between ice and sea water. As this interface of rock and ice retreats, a marine cavity develops and a flourishing ecosystem emerges.

On January 5, 2015, the WISSARD team was delayed three days in getting to its field site on the Ross Ice Shelf. The drillers on scene went ahead to create a 2,430-foot-deep ice portal. Using a highly pressurized hose, the drillers shot boiling water from melted snow straight through the shelf until they reached the glacier’s underground world. When the scientists arrived on January 8, they were eager to see for the first time what a deep grounding zone even looked like.

To unveil that realm, the team lowered “the doctor”—essentially a camera with a lamp—down the borehole. Carolyn Branecky, a UCSC graduate student on the project, described the intense anticipation she felt as they lowered the device. She and the other scientists hovered around the computer while the camera descended through the dark hole for four hours. Then, Eureka! They saw a muddy rocky layer of sediment, which told them they had reached the grounding zone.

The grounding zone is where ice that rests on land transitions to floating on ocean water. At this interface, seawater contacts the grounded ice and erodes a cavity. Like NASA technicians exploring a planet, the researchers deployed a remotely operated vehicle beneath the borehole to explore this cavity. The ROV, called a “deep SCINI,” zipped around the 2,500-foot-wide and 32-foot-deep space filled with ocean water. Along the way, it met and photographed crustaceans, fish, jellyfish and amphipods living in the dark.

WISSARD data will reveal how these creatures make this unique environment their home by investigating sources of carbon and energy used by the organisms. The results are relevant to NASA: life may exist beneath icy crusts on other worlds with deep frozen oceans, like Jupiter's moon Europa.

Next, using a geothermal probe—an instrument that looks like a giant upside-down egg beater—the team measured heat flow at the grounding zone. The 600-pound probe carved through the ice down to the muddy sediment underneath. Knowing how much heat is warming the ice from Antarctica’s rift zone is vital to calculating the ice shelf’s melting rate.

The team also collected sediment samples from the grounding zone. The type of sediment in the zone, and its texture, are other key parts of the melting puzzle. Grace Barcheck describes the dynamic between the ice sheet and the sediment beneath it as a mug sliding over a carpet. Compared to a glass coffee table, it takes more friction-generating force to push the mug over carpet. The ice sheet gets a “rug burn” as it moves over a rough layer of sediment, melting more quickly than if the base was smoother.

WISSARD researchers are using every resource they can to create a more precise model of when WAIS will hemorrhage its ice, and by how much. Their work is both exhilarating and frightening. Tulaczyk described a span of two days in 2013 when three researchers got seriously hurt, including one person who cracked his ribs from stepping in a cryoconite hole, essentially a hidden ice shaft.

The researchers aren’t risking their health in vain. For coastal communities like Santa Cruz, any melting of the West Antarctic Ice Sheet may have lasting impacts. WISSARD researchers are trying to determine when, and by how much.

The project’s impacts extend beyond Earth. The forthcoming results on how an ecosystem thrives beneath ice, says Tulaczyk, are “promising for finding life on other planets,” like the moons of Saturn or Jupiter. As WISSARD makes clear, though, there is still plenty we do not yet understand about the workings of our own world.

 

Hannah Hagemann studied Earth sciences at UC Santa Cruz. She wrote this story for SCIC 160: Introduction to Science Writing.

The Science Communication Program at UC Santa Cruz trains former scientists for careers in journalism and public outreach. The graduate program accepts applicants who already have earned degrees in science or engineering. The undergraduate course, for which this story was written, covers basic journalism skills for science majors interested in improving their writing.

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